Light or Heavy Racquet?? PLEASE HELP

I currently am using the Head IG Speed Lite becasue when I use a racquet above 275g I get really bad tennis elbow, but I find that my shots are not as powerful and there are also times when I swing to early/ fast. Is this because the racquet weighs very little?

That's one lightweight racket. Do you know the SW, which is a better indicator of power than pure weight.
Light rackets create power differently from heavier rackets. The racket must be swung faster. The ball just doesn't bounce off a really light racket as quickly as a heavier racket.
If you're swinging too early, either choke down the handle or play more. Your body will get used to the lightweight.
You only need a heavier racket IF your opponent's can consistently knock the racket out of your hands, meaning your racket spins constantly from impact with fast incoming balls.
If you don't have this problem, stay where you are.

Im not having problem with oponents and I win all of my league games, I just feel as though if I had a bit more power (maybe control but i have tight strings to allow for that). My volleying isnt very solid but could that be to lightness of the frame because when I used a 295g racquet by volleys were solid and went where I placed them

Can you say you are fully dialed into your racket?
Since a lighter racket loses more power than a heavier racket, it stands to reason your volleys are weak and short UNTIL YOU COMPENSATE! You have more time with a lighter racket, more time to take more swing, more time to turn, more time to try to move forwards.
I went from a 12 oz racket to a 10. I compensated.
It appears you are expecting all your normal shots to be normal, with a light racket.

Tennis Racquet Weight

A heavier racquet is not bad for your elbow. In fact it is better since it absorbs more of the shock causing your arm to absorb less. There are other factors that will help such as a headlight balance, a more elastic string and probably most important a flexible racquet. There is a list of these racquets and more information on this website .